Trollope's side now sit 11 points shy of a place in the top six, with the manner of Exeter's late winner being hard for the Rovers boss to swallow.
"I am disappointed to concede, especially from a set piece," Trollope said. "We have done well from them lately, we had an issue with them around October, but we have worked long and hard and we seemed to be okay with them.
"To concede in the final minute after we had pushed Exeter back for long spells was disappointing.
"We will still keep believing. There are 10 games to go and that is a lot of points to play for. We have to brush ourselves down and travel to Yeovil on Saturday, which is another local game for us and we need to produce the type of performance that we did in the second half."